The present invention relates to harvester-thresher combines in general, and more particularly to such employing more than one elongated threshing and separating element rotatable about its longitudinal axis.
In harvester-thresher combines operating with axial flow of the mowed cereal plants, it has been proposed to arrange two threshing drums next to one another, and to arrange a separate housing member provided at its lower region with cage bars around each of the threshing drums. In this construction, there are thus being used two completely independent and separate threshing units which are merely arranged next to one another in order to increase the amount of the mowed plants which the harvester-thresher combine is capable of handling, that is, threshing and/or separating into grain, straw and chaff. One very detrimental consequence of this conventional construction is that the cereal plants, after being mowed, are at first conveyed in a single stream which is subsequently subdivided into two partial streams each leading into one of the housing members for threshing therein. This subdivision is very difficult to achieve, as shown by experience, especially in view of the fact that the stems or stalks of the mowed cereal plants become intertwined in the original stream right after being cut. Thus, a not so rarely encountered problem in the combines of this construction is the formation of a bale of intertwined stalks or plants in front of the inlets of the separate housings, which means that the operation of the harvester-thresher combine must be interrupted once the occurrence of this situation has been noticed, and the jam in front of the threshing units must be manually removed in a rather time-consuming and wasteful operation. However, even in the absence of such an accumulation, the operation of the harvester-thresher combine is far from ideal, particularly due to the fact that the severed plants are unequally distributed to the two adjacent threshing units and, consequently, such units are loaded to different degrees.
A further important disadvantage of the harvester-thresher combines of this construction is that, owing to the extreme diversion of the streams of the severed cereal plants, the stalks thereof, which are to become straw, are comminuted to an undesirably high degree. This has several deleterious consequences, namely, that the straw has a high proportion of short separate sections, that undue burden is put on the airstream segregating arrangement, and that, as a result of this, there is an undesirably high amount of grain loss downstream of the harvester-thresher combine.